1. Field of the Invention
The present invention relates to image display units using linear display devices and to display terminals.
2. Description of the Related Art
Conventionally, liquid crystal display (LCD) panels or digital micromirror devices (DMD™) have been used in projection display systems. Recently, a Grating Light Valve (GLV™) display, employing a grating which is made by micro-machining and which is driven by an active matrix, has been developed. The GLV display has drawn public attention.
A GLV device has many advantages over known spatial light modulators. Specifically, the GLV device can display seamless, bright images, can be manufactured at a low cost using micro-machining technology, and can operate at high speed.
The need to provide copy protection of image information and digital information and the need to perform scrambling arise in various types of displays. The above-described GLV device is also required to perform these processes.
Conventionally, in order to perform copy protection of image information and digital information and scrambling, all apparatuses, such as set top boxes (STB) and video cassette recorders (VCR), which are connected to an image display unit are required to be capable of performing copy protection and scrambling. As a result, the structure of each apparatus becomes complicated, and thus the cost of each apparatus increases.
The STB is required to perform complex image processing in order to scramble an image.
When protection is decrypted by the STB, the reality is that there is no way to prevent copying of image information and digital information.
If each display terminal is given an identification number, the identification number can be used to identify the display terminal (user terminal), so that distribution and billing can be performed.
It is difficult to record such an identification number in known image display devices.